1. Field of the Invention
The present invention generally relates to optically-readable identification means, such as bar codes, and, more particularly, to a method of producing an article having such identification means protectively embedded in the article.
2. Background Art
While the present invention is described as being applied to bar codes, it will be understood that it may be applied as well to other optically-readable identification means suitable for embedding by the methods described herein.
Bar codes have found application in a variety of applications as an information source, typically for digital processors. Such codes are used at point-of-sale merchandising for pricing and inventory count, in controlled personnel access systems, in manufacturing for work-in-process and inventory control, and for subsequent article identification after manufacture, to name only a few applications. The bar codes themselves comprise a series of parallel lines, with each line typically in the range of 1/8" to 1' in length and 1 to 50 mils in thickness, and are usually printed with black ink on a white background. The lines may variously have unequal spacing and/or unequal thickness, with the variations in spacing and/or thickness determined by the information "stored" in the bar code. A bar code is "/read" by serailly illuminating the bars, with the bars absorbing the and the background reflecting the. The resulting pattern of reflection and nonreflection is sensed by a light detecting device which provides input to the digital processor.
Typically, the bar codes are printed with carbon ink on a paper or plastic substrate and adhesively attached to an article. When some articles such as machinery and equipment are to be identified, the bar code may be attached to a metal or plastic tag which may be riveted or screwed to the article. While such an arrangement is satisfactory for many applications, these externally-applied labels or tags are subject to being removed, such as by physical abrasion, vandalism, weathering, and/or exposure to liquids, for example. Additionally, where a tag is attached by means such as screwing or riveting, the integrity of the article to which the tag is attached may be comprised. The problem may also exist where the bar code is ground or etched into the surface of the article. Also, most such bar codes are unsatisfactory for use at high temperatures, say on the order of 500 degrees Fahrenheit, because the wax usually used in the carbon ink may melt and run and/or the paper or plastic substrate may char or burn.
When the bar code is to be used at high temperatures, it may take one of two forms. In one, a metal light-reflective surface, say an aluminum plate, is provided for attachment to the article and the bar code is placed on the plate using a high temperature paint. In the other, when the physical properties of the article permit, the bar code may be ground or etched into the surface of the article itself. Each one of these known methods is expensive and time-consuming.
Accordingly, it is a principal object of the present invention to provide a bar code or other identification means which is protectively embedded in the article to be identified and becomes an integral part thereof.
It is an additional object of the present invention to provide such a bar code suitable for use at high temperatures.
It is a further object of the present invention to provide such a bar code that can be easily and conveniently embedded in an article.
Other objects of the present invention, as well as other particular features and advantages thereof, will, in part, be obvious, and will, in part, be apparent from the following description and the accompanying drawing figures.